Sunmi just saw her boyfriend cheating on her. Her boyfriend dances with his ex-girlfriend and it breaks Sunmi's heart. You as her friend hug her tightly to comfort her

She keeps crying at you and you can't see her like that so you hold her waist and hand to start dancing with her. Sunmi was surprised by that but she seemed to enjoy it so you kept smiling at her while continuing to dance

She slowly blushed when you still gently touched her waist. It's a romantic dance